Urothelial Carcinoma of the Bladder with a Single Pancreatic Metastasis: A Case Report

<b>Background and Clinical Significance</b>: Bladder cancer is common, with urothelial carcinoma (UC) comprising most cases in Western countries. Metastases usually involve pelvic structures, lymph nodes, and organs such as the liver, lungs, bones, and adrenal glands. Identifying unusual metastatic sites is critical for accurate diagnosis and treatment planning. <b>Case Presentation</b>: A 65-year-old man with a history of high-grade (G3) UC and carcinoma in situ, previously treated with TURBT, second-look resection, and SWOG-protocol BCG, presented with a new bladder lesion (pT1). Staging CT revealed extravesical spread and a 1.5 cm pancreatic body nodule. EUS-guided biopsy confirmed metastatic UC with concordant immunohistochemistry (GATA3+), excluding primary pancreatic cancer. The patient was referred for systemic therapy with immune checkpoint inhibitors and Enfortumab Vedotin. <b>Conclusions</b>: This case demonstrates the rare occurrence of pancreatic metastasis from bladder UC. EUS-guided biopsy with immunohistochemistry is essential to distinguish secondary lesions from primary pancreatic tumors. Accurate diagnosis is crucial to guide systemic therapy, particularly with emerging immunotherapy and antibody-drug conjugates.